在 PHP 中合并来自不同数据库的两个 mysql 查询

Question

我需要将来自两个数据库的一对 MySQL 查询合并到一个单独的多维关联数组中。下面是我正在处理的数据示例。

问题似乎与生成的 $data0 数组值缺少唯一键（理想情况下是相应的“sku”值）有关，以用作合并数据的索引。

期望的输出是：

Array (
    [0] => Array (
        [SKU] => 101
        [Description] => Test Item 1
        [On Hand 1] => 3
        [On Hand 2] => 7
    )
    [1] => Array (
        [SKU] => 102
        [Description] => Test Item 2
        [On Hand 1] => 11
        [On Hand 2] => 15
    )
)

可能有更好的方法来处理 MySQL 查询和所需的数组。如果是这样，请告诉我。请提供任何反馈，因为我是一名排名初学者，并将尽我所能获得的帮助。谢谢！

<?
$query1 = "SELECT sku, description, on_hand as 'On Hand 1' FROM database1"

$queryresult1 = mysql_query($query1, $connection1);

$data1 = array();
while ($resultrow1 = mysql_fetch_assoc($queryresult1)) {
    array_push($data1, $resultrow1);
}

$query2 = "SELECT sku, on_hand as 'On Hand 2' FROM database2"

$queryresult2 = mysql_query($query2, $connection2);

$data2 = array();
while ($resultrow2 = mysql_fetch_assoc($queryresult2)) {
    array_push($data2, $resultrow2);
}

$data0 = array_merge($data1, $data2);

//example code for troubleshooting
$data1 = array('101' => array('SKU' => '101', 'Description' => 'Test Item 1', 'On Hand 1' => 3), '102' => array('SKU' => '102', 'Description' => 'Test Item 2', 'On Hand 1' => 11));
print_r($data1);
echo "<br /><br />";
$data2 = array('101' => array('SKU' => '101', 'On Hand 2' => 7), '102' => array('SKU' => '102', 'On Hand 2' => 15));
print_r($data2);
echo "<br /><br />";
$data0 = array_merge($data1, $data2);

print_r($data0);
?>

Answer 1

通过循环遍历$data1 中的每个键，您可以使用当前的$key 从$data2 检索值。这将为您提供所需的结果：

$data1 = array('101' => array('SKU' => '101', 'Description' => 'Test Item 1', 'On Hand 1' => 3), '102' => array('SKU' => '102', 'Description' => 'Test Item 2', 'On Hand 1' => 11));
$data2 = array('101' => array('SKU' => '101', 'On Hand 2' => 7), '102' => array('SKU' => '102', 'On Hand 2' => 15));

$data0 = array();
foreach($data1 as $key => $data){
    $data['On Hand 2'] = $data2[$key]['On Hand 2'];
    $data0[] = $data;
}
unset($data1, $data2);

print_r($data0);

Answer 2

您最好使用单个 UNION 查询来解决这个问题：

SELECT sku, description, on_hand as 'On Hand 1' FROM database1
UNION ALL
SELECT sku, null       , on_hand as 'On Hand 2' FROM database2

注意null 用于database2 查询中的描述字段。 UNION 成员查询的列数和类型必须相同。

那么这很简单：

while($row = mysql_fetch_assoc($result)) { 
    $data[] = $row;
}

不需要两个查询、两个 fetch 循环和稍后的合并。

Answer 3

<?php
// connection 1
$connection1= mysql_connect("localhost","root","");
//selecting database 1
mysql_select_db("database1",$connection1);
// select query from the database1 and table 1
$query1 = "SELECT sku, description, on_hand as 'On Hand 1' FROM database1.table1";
$queryresult1 = mysql_query($query1, $connection1);

$data1 = array();
while ($resultrow1 = mysql_fetch_assoc($queryresult1)) {
    array_push($data1, $resultrow1);
}
//connection 1
$connection2= mysql_connect("localhost","root","");
//selecting database 2
mysql_select_db("database2",$connection2);
// select query from the database2 and table 2
$query2 = "SELECT sku, on_hand as 'On Hand 2' FROM database2.table2";

$queryresult2 = mysql_query($query2, $connection2);

$data2 = array();
while ($resultrow2 = mysql_fetch_assoc($queryresult2)) {
    array_push($data2, $resultrow2);
}

$data0 = array_merge($data1, $data2);

print_r($data0);
?>

Answer 4

您可以通过使用JOIN 语法在查询中连接两个表来做到这一点：https://dev.mysql.com/doc/refman/5.0/en/join.html

那么您的查询将如下所示：

SELECT
    table1.sku,
    table1.description,
    table1.on_hand as 'On Hand 1',
    table2.on_hand as 'On Hand 2'
FROM
    database1.table1 JOIN
    database2.table2 ON table1.sku = table2.sku

两个表中的行将相互连接，其中 sku 字段值相互对应。如果您想要 table1 和 table2 中的所有结果，可以创建LEFT JOIN。